N-substituted carbamoyl chlorides and method of preparation

ABSTRACT

N-alkyl-N-chlorothiocarbamoyl chlorides and their method of preparation by reacting alkyl isocyanates with sulfur dichloride. The carbamoyl chlorides are useful intermediates in the preparation of pesticides.

United States Patent Kohn Oct. 17, 1972 [54] N-SUBSTITUTED CARBAMOYL[56] References Cited CHL RID P METHOD OF UNITED STATES PATENTS [72]Inventor: Gustave K'Kohn, BerkeleyrCaM 3,282,950 11/1966 Ottman......260/306.7 [73] Assignee: Chevron Research Company, San PrimaryExaminer-Lorraine A. Weinberger Francisco, Calif. AssistantExaminer-Richard D. Kelly Attorney-J. A. Buchanan,- John Stoner, Jr., G.F. [22] Flled' June 1970 Magdeburger and Raymond Owyang [21] -Appl.No.:45,901

[57] ABSTRACT u s N-alkyl-Nchlorothiocarbamoyl chlorides and their260/553 method of preparation by reacting alkyl isocyanates with sulfurdichloride. The carbamoyl chlorides are 51/58 8 useful intermediates inthe Preparation of pesticides.

8 Claims, No Drawings N-SUBSTITUTED CARBAMOYL CHLORIDES AND METHOD OFPREPARATION FIELD OF THE INVENTION The present invention is directed toN-alkyl-N- chlorothiocarbamoyl chlorides and their method ofpreparation. The carbamoyl chlorides are useful as intermediates in thepreparation of pesticides.

DESCRIPTION OF THE INVENTION The carbamoyl chlorides of the presentinvention may be represented by the formula:

wherein R is alkyl of from one to carbon atoms, alkyl of fromone to 10carbon atoms substituted with halogen atoms of atomic number 17 to 35(chlorine and bromine),cyloalkyl of five to 10 carbon atoms orcycloalkyl of five to 10 carbon atoms substituted with halogen atoms ofatomic number 17 to 35; preferably the haloalkyl radical orhalocycloalkyl radical will contain one four halogen substituents,preferably one two halogen substituents.

More preferably R is alkyl of one to six carbon atoms, alkyl of one tosix carbon atoms substituted with one to four halogen atoms of atomicnumber 17 to 35, preferably one to two halogen atoms of atomic number 17to 35, cycloalkyl of five to six carbon atoms or cycloalkyl of five tosix carbon atoms substituted with one to four halogen atoms of atomicnumber 17 to 35, preferably one to two halogen atoms of atomic number 17to 35.

Still more preferably R is alkyl of one to four carbon atoms or alkyl ofone to four carbon atoms substituted with one to two halogen atoms ofatomic number 17 to 35.

Examples of representative R groups include:

2 catalyst, such as for example dibutyl tin dilaureate, tetraethylammonium chloride and triethylamine. The preferred catalyst istetraethyl ammonium chloride. Although the reaction will also proceedwithout the presence of a catalyst, a catalyst is preferred. Generallyabout 1 percent to 50 percent by weight of catalyst based on isocyanateis sufficient. Preferably the catalyst is removed before isolation ofthe carbamoyl chloride product or before in situ reaction with asuitable reactant to produce the insecticidal product described furtherhereinafter.

The reaction is preferably accomplished at a temperature of from -50 to100C. and at ambient or airtogenous pressure. The reaction time willgenerally run from V4 to 72 hours, more usually A to 24 hours.

The carbamoyl chloride product can be recovered by stripping sulfurdichloride and then distilling the desired product from the mixture.When the catalyst is insoluble, the carbamoyl chloride product can beThe carbamoyl chlorides of the present invention are 7 made by thereaction of an isocyanate and SCI, in accordance with the followingreaction:

wherein R is the same as defined above. The sulfur dichloride/isocyanatemolar ratio should be at least 1:1. The sulfur dichloride is preferablypresent in excess. For best results it is necessary that thesulfurdichloride be in excess of 95 percent, preferably 99 percent,pure.

The reaction can be accomplished in the presence of a suitable inertorganic solvent or neat. Preferably the,

recovered by stripping sulfur dichloride, filtering the insolublecatalyst and then evaporating off the low boiling solvent.

Examples of suitable carbamoyl chlorides prepared by the subjectreaction include: N-methyl-N- chlorothiocarbamoyl chloride, N-ethyl-N-chlorothiocarbamoyl chloride, N-n-propyl-N- chlorothiocarbamoylchloride, N-n-butyl-N- chlorothiocarbamoyl chloride, N-isopropyl-N-chlorothiocarbamoyl chloride, N-n-pentyl-N- chlorothiocarbamoylchloride, N-chloromethyl-N- chlorothiocarbamoyl chloride,N-bromo-rnethyl-N- chlorothiocarbamoyl chloride, N-cyclopentyl-N-chlorothiocarbamoyl chloride, N-cyclohexyl-N- chlorothiocarbamoylchloride, N-halocyclohexyl-N- chlorothiocarbamoyl chloride.

The compounds of the present invention are useful intermediates in thepreparation of pesticides. Thus the carbamoyl chlorides of the presentinvention may be used to produce N-alkyl-N-(chlorocycloalkylthio) ureaswhich have pesticide, particularly herbicide activity. These compoundsare prepared by the reaction of N-alkyl-N-chlorothiocarbamoyl chloridewith a cyclic unsaturated hydrocarbon and then with ammonia or an amine.Thus, e.g., N-methyl-N-(Z-chlorocyclohexylthio)-N'-phenyl urea can beprepared by reacting N-methyl-N-chlorothiocarbamoyl chloride of thepresent invention with cyclohexene and the resulting product reactedwith aniline in accordance with the following general reaction scheme:

The present invention will be more fully understood by reference to thefollowing examples.

EXAMPLE 1 14.3 g. of methyl isocyanate (molecular weight 57.05) and 5 g.of tetraethyl ammonium chloride were dissolved in 100 ml. ofdichloromethane. Sulfur dichloride (25.8 g.) of greater than 98% puritywas added dropwise. The reaction was slightly exothermic.

The reaction mixture turned yellow within about minutes. Thedichloromethane was evaporated and the product separated from thetetraethyl ammonium chloride salt by hexane extraction. The hexane wasthen evaporated and the product distilled. The fraction boiling at3235C/0.2 mm was chemically analyzed forN-methyl-N-chlorothiocarbamoylchloride:

Calculated Found N 9b 8.75 8.12 Cl 44.31 44.18 s 20.04 19.68

Infrared analysis and proton magnetic resonance analysis were as used toconfirm the structure.

EXAMPLE 2 MethyLisocyanate 11.4 g. (0.2 moles) and sulfur FoundCalculated N k 8.75 8.34 Cl 44.4 45.00 S 20.04 19.95

EXAMPLES 14.3 g. of methyl isocyanate and 25.8 g. of sulfur dichloridewere reacted neat withouta catalyst-and in the absence of light. After28 days the reaction mixture turned yellow.N-methyl-N-chlorothiocarbamoylchloride was produced.

EXAMPLE 4 19.8 g. of n-butyl isocyanate and 20.6 g. of sulfur dichloridewere put into a vial, neat, in the absence of a catalyst and reacted inthe presence of sunlight. The reaction mixture turned yellow. Analysisindicated a formation of N-n-butyl-N-chlorothiocarbamoyl chloride.

EXAMPLE 5 The same reactants as in Example 4 in approximately the samequantities were placed in a pressure tube which was sealed and placed ina boiling water bath for 6 hours. At the end of this period of time thereaction mixture was orange and after standing for about Z days theproduct became pale yellow. Analysis of the stripped product indicatedN-n-butyl-N-chlorothiocarbamoyl chloride:

Calculated Found N. 6.93 6.68 Cl 35.08 35.23 S b 15.87 15.62

EXAMPLE 6 n-Butyl isocyanate (19.8 g.) and tetraethyl ammonium chloride(5 g.) werev dissolved in 100 ml. of dichloromethane. 20.6 g. of sulfurdichloride was slowly added dropwise. After about 15 minutes thereaction mixture turned yellow. The dichloromethane was evaporated. Theproduct was taken up in hexane and separatedfrom the catalyst. The.hexane was then evaporated. N-n-butyl-N-chlorothiocarbamoyl chloride wasproduced.

Other reactions were carried out in the presence of solvents suchas-dimethylfuran and tetrahydrofuran, and in the presence of catalystssuch as dibutyl tin dilaureate and triethylamine.

As will be evident to those skilled in the art, various modifications onthis invention can be made or followed, in the light of the foregoingdisclosure and discussion, without departing from the spirit or scope ofthe disclosure or from the scope of the following claims.

I claim: I

'1. Compound of the formula R-Nii-C1 lei wherein R is alkyl of one to 10carbon atoms, alkyl of one to 10 carbon atoms substituted with one tofour halogen atoms of atomic number '17 to 35, cycloalkyl of five to 10carbon atoms or cycloalkyl of 5 to 10 carbon atoms substituted with oneto four halogen atoms of atomic number 17 to 35.

2. Compound of claim 1 wherein R is alkyl of one to six carbon atoms,alkyl of one to six carbon atoms sube stituted with one to four halogenatoms of atomic number 17 to 35, cycloalkyl of five to six carbon atomsor cycloalkyl of five to six carbonatoms substituted with one to fourhalogen atoms of atomic number 17 to 3. Compound of claim 2 wherein R isalkyl of one to six carbon atoms substituted with one to two halogenatoms of atomic number 17 to 35 or cycloalkyl of five to six carbonatoms substituted with one to two halogen atoms of atomic number 17 to35.

4. Compound of claim 1 wherein R is alkyl of from n-ay-c-ci s or whereinR is alkyl of one to carbon atoms, alkyl of one to 10 carbon atomssubstituted with one to four halogen atoms of atomic number 17 to 35,cycloalkyl of five to 10 carbon atoms or cycloalkyl of five to 10' thepresence of a catalyst selected from the group consisting of dibutyl tindilaurate, tetramethyl ammonium chloride and triethylamine, at atemperature of -50C to C.

8. The method of claim 7 wherein the catalyst is tetramethyl ammoniumchloride.

2. Compound of claim 1 wherein R is alkyl of one to six carbon atoms,alkyl of one to six carbon atoms substituted with one to four halogenatoms of atomic number 17 to 35, cycloalkyl of five to six carbon atomsor cycloalkyl of five to six carbon atoms substituted with one to fourhalogen atoms of atomic number 17 to
 35. 3. Compound of claim 2 whereinR is alkyl of one to six carbon atoms substituted with one to twohalogen atoms of atomic number 17 to 35 or cycloalkyl of five to sixcarbon atoms substituted with one to two halogen atoms of atomic number17 to
 35. 4. Compound of claim 1 wherein R is alkyl of from one to fourcarbon atoms.
 5. Compound of claim 4 wherein R is methyl.
 6. Compound ofclaim 4 wherein R is butyl.
 7. Method of preparation of the compound ofthe formula wherein R is alkyl of one to 10 carbon atoms, alkyl of oneto 10 carbon atoms substituted with one to four halogen atoms of atomicnumber 17 to 35, cycloalkyl of five to 10 carbon atoms or cycloalkyl offive to 10 carbon atoms substituted with one to four halogen atoms ofatomic number 17 to 35, which comprises reacting an isocyanate of theformula R - N C O, wherein R is as defined above, with sulfur dichLoridein the presence of a catalyst selected from the group consisting ofdibutyl tin dilaurate, tetramethyl ammonium chloride and triethylamine,at a temperature of -50*C to 100*C.
 8. The method of claim 7 wherein thecatalyst is tetramethyl ammonium chloride.